Study on sliding layer of cross-tensioned concrete pavement

In order to reduce the number of transverse joints and improve the cracking resistance of Portland cement concrete pavement, a series of diagonally arranged prestressed tendons are applied in the pavement slab, defined as cross-tensioned concrete pavement (CTCP). However, the reduction in the number of transverse joints causes additional stresses and deformations within the CTCP slab which cannot be addressed by only increasing the level of prestress applied to the slab. It is necessary to lay a well-designed sliding layer between the base and the CTCP slab to reduce the stresses and deformations. The influence of coefficient of friction (COF) of a sliding layer on the CTCP structure was studied using both finite element analysis and analytical solutions. Results show that the sliding layer with a smaller initial (before final post-tensioning) COF can reduce the stresses caused by wheel and thermal load while maintaining the prestress in the CTCP slab. Larger long-term (after final post-tensioning) COF of the sliding layer can minimise the CTCP slab end movements. However, the long-term COF should not be larger than 1.04. In addition, a coefficient of friction tester for the CTCP sliding layer was designed and developed based on the Amonton law. Optimum structure parameters and type of the CTCP sliding layer were obtained using "Sand + Polyethylene-plastic Sheeting" as a sliding layer. The optimum cement content of the "Sand + Cement + Polyethylene-plastic Sheeting" sliding layer was also determined from the experimental results.